the firmest ground

the firmest ground (cogito ergo cogito)

photographs by evan hartzell

curated by michael lebuffe

Descartes says that ideas are thoughts that are of things and that only clear and distinct ideas are knowledge. Suppose that a thought is imagistic if it is or is like seeing, touching, hearing, smelling, or tasting. Descartes says, I think, that no imagistic ideas are clear and distinct ideas of external things. I can know color clearly and distinctly in my visual idea of a leaf if I know that the color is a property of my idea, Descartes would allow. But my idea is not an external thing. He would not allow that I could know the external thing, the leaf, clearly and distinctly in an imagistic idea.

Descartes thinks that he can show that we cannot know external things clearly and distinctly in our imagistic ideas. He argues that a leaf is capable of infinite changes, and we can know this, but we cannot imagine all of the infinite changes. Our knowledge of the leaf, then, if we know it, cannot be imagistic.

Sometimes readers of Descartes get confused, or maybe they are on to something, with the notion that ideas are thoughts of things. The leaf is a thing, so my thought of it is one idea. The idea of the leaf is a different thing from the leaf, so my thought of the idea of the leaf is a different idea from the first idea. The first idea, after all, is of a leaf, but the second idea is of an idea. Following this line of thought, if I know color clearly and distinctly as a property of my idea of the leaf, what is clear and distinct is not my imagistic idea of a leaf, but my imagistic idea of my idea of the leaf.

That may be wrong, as an interpretation of Descartes, but what it involves is right: knowledge and ideas are of things. Knowing what you know and what you do not know in large part must be knowing what a given idea is of. I am a thinking thing, Descartes says, so this must be a basic task. –michael lebuffe